Spark-plug.



W. S. BROWN.

SPARK PLUG.

APPLICATION IILED' MAR. 14, 1912.

Patented Feb. 16, 1915.

' pfrzyerforl {1/1711 5 5. Brow/2 VIILLIS S. BROWN, OF BF IDI BRE, ILLINOIS.

SPARK-PLUG.

Specification of Letters .latcnt.

Patented Feb. 16, 1915.

Application filed March 14, 1912. Serial No. 683,740.

.of Illinois, have invented certain new and useful Improvements in Spark-Plugs, of which the following is a specification.

My invention relates to sparking devices or plugs for ignition systems, and the ob ject of my invention is to provide an im-- proved spark plug which will be simple, durable and reliable and practically indestructible in construction, and effective and efficient in operation and service.

To the attainment of these ends and the accomplishment of other new and useful objects hereinafter appearing, my invention consists in the features of novelty in the construction, combination and arrangement of parts herein described and claimed, and shown in the accompanying drawings which illustrate one embodiment of my invention, and in which- Figure 1 is central longitudinal sectional view of a spark plugembodying my invention; Fig. 2 is a transverse sectional view on line 22 of Fig. 1; and Fig. 3 is a perspective view of the yielding sleeve member.

In the drawings I have shown my invention as embodied in the type of spark plug which is adapted to be screwed into a suitable threaded opening in the combustion chamber of an internal combus tion engine, hence I have shown the body member or shell 1 threaded externally at its lower portion 2 for this purpose. This body member is hollow and circular and its lower end terminates in a bridge or span 3 preferably integral therewith and forming an outer or ground electrode for the plug. The body member has a hexagonal exterior portion 4, which furnishes a means by which a wrench may grip it to screw the plug into or out of the opening in the combustion chamber of the engine. About midway of its endsthe body member has an annular interior ledge or shoulder 6. A porcelain or other suitable insulator 7 extends into the body member from the top. This insulator sleeve is preferably circular in section and has an annular enlargement 8 which is seated or clamped against the ledge or shoulder 6 by means of a hollow removable bushing or sleeve 9 and a screw cap or clamping member 10, both of which surround the insulator. The shoulders 11 and 12 formed by enlargement 8 are tapered so as to insure a centering of the insulator when clamped in position. Between the body shoulder 6 and the enlargement there is a gasket 13 of an suitable material which seals the joint against the leakage of gases. The sleeve or bushing 9 is slotted or divided and slightly flared at its lower end M, as shown in Fig. 3, so that it will yieldingly press upon the insulator enlargement. The upper end 15 of the bushing is beveled and formed to engage the inclined interior shoulder 16 in the cap or clamping member 10 as clearly shown Fig. l.

The insulator sleeve has a longitudinal bore 17 enlarged near its lower end to form a shoulder 18. An electrode stem 19 threaded for the greater portion of its length extends through this bore and protrudes from both ends thereof. Near the lower end of its threaded portion it carries a threaded collar 20 which is clamped against the shoulder 18 by means of a nut 21 on the upper end of the threaded stem, for the purpose of securing the stem in position. Between the nut :51 and the upper end of the insulator is a spring washer 21 and between the collar 20 and shoulder 18 is a packing gasket, these being provided for the purpose of preventin; the insulator from cracking due to pres-- sure and expansion of the parts. A binding screw 23 is also provided upon the upper end of the stem whereby an electric conductor may be fastened to the plug. The lower end of the central electrode stem carries an elliptical button 24: of the same or different material as the stem. This button is disposed within a circular hole or opening 25 in -the bridge member 3 and is annularly spaced therefrom to form a suitable spark gap.

It will thus be noted that my improved plug possesses many advantages from a manufacturing and a service standpoint. The use of a separate sleeve or bushing 9 makes it self-adjusting to any inaccuracies or irregularities in manufacture of the parts. The bushing may be made of any suitable material which is found best adapted to yield and prevent the porcelain from cracking from the heat pressure, whereas the body and cap may be made of steel or such material as will render the device strong and durable. The button electrode forms a very satisfactory sparking terminal and is protected from injury by the strong rigid bridge or span electrode 3. The parts may be readily disassembled for cleaning or other purpose and as readily assembled, and, as previously mentioned, will adjust themselves when clamped so that the central electrode will always return to its central posi-' tion.

What I claim as new is 1. In a spark plug of the class described, the combination of a hollow plug member having a ground electrode at its lower end and having an inclined annular shoulder, an insulator disposed within said plug memher and having an annular tapered enlargement resting against said shoulder, a sleeve surrounding said insulator and having a slotted yielding portion adapted to co-act with said enlargement, a cap member on said plug member arranged to force said sleeve against said enlargement whereby to yield ingly maintain said insulator in position, an electrode extending through and supported by said insulator and disposed in sparking relation to said ground electrode.

2. In a spark plug of the class described, the combination of a hollow plug member having a ground electrode at its lower end and having an inclined annular shoulder, an insulator disposed within said plug member and having an annular tapered enlargement resting against said shoulder, a sleeve surrounding said insulator and having a slotted yielding portion adapted to want with said enlargement, and a beveled upper end, a cap member on said plug member arranged to engage said beveled end, and adapted to force said sleeve against said enlargement, whereby to yieldingly maintain said insulator in position, an electrode extending through and supported by said insulator and disposed in sparking relation to said ground electrode.

8. In a spark plug the combination with a hollow plug having an internal annular seat, of an insulator extending within the the insulator acted upon by the; clamping member to form a fluid tight joint between the insulator and clamping member and to resiliently maintain the insulator seated .in the plug.

5. In a spark plug the combination with a hollow plug, of an insulator seatedtherein, a glamping member on the plug, and an independent sleeve of spring material about the insulator, slotted at its lower end and acted upon by the clamping member to form a fluid tight joint between the insulator and clamping member and to yieldingly maintain the insulator seated in the plug.

6. In a spark plug the combination with a hollow plug, of an insulator seated therein, a clamping member on the plug, and an independent sleeve of spring material about the insulator beveled at its upper end and slotted at its lower end and acted upon by the clamping member to form a fluid tight joint at its upper end between the insulator and clampingmember' and to yieldingly' maintain the insulator seated in the plug.

In tesitmony whereof I have signed my name to this specification, in the presencc of two subscribing witnesses, on this 9tl' (lay of March A. D. 1912.

WILLIS 's. BROWN.

Witnesses THoMAsA. WILLARD, CHARLES D. Loor. 

